Grading mechanism, a scale and method of forming said scale for lastturning lathes



E. J. PRINDLE.

GRADING MECHANISM, A SCALE AND METHOD OF FORMING SAID SCALE FOR LASTTURNING LATHES.

APPLICATION FILED APR. 25. 1918.

1,334,400. Patented Mar. 23, 1920.

4 $HEETSSHEET I.

M T ATTORNEYS,

E. J. PRINDLEA GRADING MECHANISM, A SCALE AND METHOD OF FORMING SAIDSCALE FOR LAST TURNING LATHES. APPLICATION FILED APR-25,1918- 1 534,400.Patented Mar. 23, 1920.

4 SHEETS-SHEET 2. P

HUN

3Z9 Z8 Z6 33/ 1 NH 1| ll -'66; 24

L5 I INVENTOR w A Y A 'WWAS E. J. PRINDLE. GRADING MECHANISM, A SCALEAND METHOD OF FORMING SAID SCALE FOR LAST TURNING LATHES.

APPLICATION FILED APR. 25, 1913.

Patented Mar. 23, 1920a 4 SHEETSSHEET 3.

E. J. PRINDLE. GRADING MECHANISM, A SCALE AND METHOD OF FORMING SAIDSCALE FOR LAST TURNING LATHES.

APPLICATION FILED APR.25,19I8.

1,334,400. Patented Mar. 23, 19:20.

. 4 SHEETS-SHEET 4-.

INVENTOR ornroii.

EID'WIN J. PRINDL'E, t'JF EAST 0 MMNGE, NEW JERSEY, ASSIGNOR, BYIVL'ESNE ASSIGN- MENTS, TO FITZ-liiMI'lIRE DOUBLE PIVOT L ST OOll'llANY,OF AUBURN, MAINE, A

CUIEL-PGRATIUN O13 MAINE.

GRADING IllIECHANISM, A SCALE AND ll'llllltHiZlIJ O1 liClRMINE-l SAIDElCALE FOR LAST- TURNING LELTlE-EES.

nae lace.

Specification of Letters Patent.

Patented Mar. 23, 1920.

Application filed April 25, 1918. Serial No. 230,621.

his invention relates to grading mechanisms used in pattern copyingmachines, and is di ilosed as embodied in a last lathe. iho ential partsof a pattern copying machine are four supporting instrumentalt ti whichneed not all be movable, tor the tracing point or model wheel, the tool,the model. and the work, respectively, and grading mechanisms forregulating the relative movements of these instrumentalities to malrethe relative movement of the tool an d work geometrically orpantographically related to that of the tracing point and model in oneor more dimensions.

in the grading o1? lasts, the successive se tings oi? the length gradingmechanis r while simply ariithmetically related as tar as any one modelis concerned, are not the same for the same sizes graded for differentinoels. This is because lasts of the same ma l'ed size are not of thesame length, owing to dill erences in style, and the successive sizesdiffer in length by a constant arbitrary length unit, as inch,regardless of the actual. length of the model. For eic ample, if themodel 7 is 11 inches long, the ill, and 10 are 11-1,, 11% and 12 incheslong respectively, and the corresponding magnil'ication ratios are whileit the model 7 is 11 inches long, the correspondin ratios are 35 n 2 1iii s4 s4;

lfhc dilliculty of making the grader setclear, and exact descriptionting in such a system is obvious. In practice in machines as heretoforeconstructed, this dilliculty has been dealt with by a somewhat clumsyand unsatisfactory construction. These machines had a single uni tormlygraduated length grading scale which was us d to grade from any model bychanging the vertical. position of the lower grading lever pivot, incorrespondence with the model length, thus changing the advantage of thelever so that the grad iiig scale would work with it to produce suecessive increments elf inch in the lasts out. lt is advisable also, inmachines 0t this type, to hcep the lower pivot opposite the center oi?the model, and the two objects were at tained by moving the pivot alonga sloping bar which would position the pivot at the proper verticalelevation when it was under the model center. \Vhile this constructionis capable of good work, it was hard to set accurately, and inconsequence there was l'llUlU or less jockeying with. the adjustments atthe lower pivot point and at the scale. The setting of the lower pivotwas also a :t'ruitit'ul source of error, as the abso lute length o'l'the model. last would never in practice have any value simplyexpressible in inches, or in size notation.

it is the object of the present invention to avoid these and otherditiiculties and to provide a granting mechanism which will be simple inadjustment and accurate in use. lajcoirclin ly an important feature ofthe invention re ides in a novel organization comprising a universalchart of grading scales continuously in operative relation to anadjustable member oi the grading mechanism, for setting this member toany de sired grade from any ength of model.

Another feature oi the invention is the solution oi the problem oikeeping the lower lever pivot opposite the model center. The necessityof raising and lowering this pivot with its entailed diliiculty ofaccurate adjustment and loss of time has been avoided by the provisionof the universal grading scale, and it is only necessary that it bemoved laterally. The present invention provides a mechanical modelmeasuring means for setting the pivot accurately opposite the center ofthe model.

The above remarks will be better understood by reference to thefollowing description of a preferred embodiment of the invention,selected for purposes of illustration and shown in the drawings in whichFigure 1 is a front elevation of the machine;

Fig. 2 is an enlarged detail of the mechanism V Fig. 3 is a section onthe line 3-3 of Fig. 2;

Fig. 1 is a section on the line H of Fig. 2

Fig. 5 is a side View of in Fig. 2;

Fig. 6 is a section on the line 6-6 of Fig. 2;

Fig. 7 is a section on the line 77 of Fig. 2; 7

Fig.8 is a detail.

Fig. 9 is a developed View oi the scale.

Fig. 10 is a diagram illustrating the grading mechanism.

While my invention is capable of embodiment in many 'difl erent forms, Ihave illustrated it by the best embodiment thereof known to me, and suchembodiment is to be regarded only as typical of many possibleembodiments, and my invention is not to be confined to the illustratedembodiment.

In the illustrated embodiment, the invention is shown as applied to anordinary Blanchard, or last-turning lathe. The lathe consistsessentially of the usual bed 1, supported upon legs, the bed having uponit a model-wheel carriage 2 c ying model wheel 3, and cutter carriage ein pillars upon which a cutter head 5 is mounted, the cutter head, whenrevolving, making a solid of revolution usually of the same size as themodel wheel. The model-wheel carriage and the cutter carriage aremounted on a guide 6 on the bed, and one oi them (usually the cuttercarriage) is moved along with the guide by power, and motion istransmitted from such carriage to the model-wheel carriage throughgrading mechanisn'i, as will be more fully described later. From thetable rise stationary side frames 7 and 8, which at-their upper endssupport a shaft 9 on which is hung a swing frame consisting of endframes 10 and 11, carrying guide bars 12 and 13," The guide bars 12 and13, like the ways of an ordinary turning lathe, carry a head stock inwhich is mounted a model head stock spindle and a heel dog 14, and amodel tail stock 15 carrying a toe dog 16 for the model last, which isto be used 'rading the parts shown as a model in reproducing the new ist desired. The guide bars 12 and 13 also carry a'blOCl-Z head stock 17,with its heel dog 18,

and a block tail stock 19, with its too dog 20, that are to support therough block from which the last is to be formed.

In the operation of the lathe, the weight of the swinging frame normallydraws the latter toward the model wheel until the model last restsagainst the model wheel. As the model revolves, it swings the swingframe back and forth so that the cutter head cuts out of the block orblank :1 new last which is the same shape in cross-section as the oldone. The carriages of the model wheel and cutter head are caused totravel lengthwise of the main frame, so that all parts of the modelsurface are presented to the model wheel and the corresponding parts ofthe new last are shaped.

In order to obtain a new last of the de sired longer or shorter sizethan the model, a grading mechanism is used to transmit motion of themodel. carriage from the cuti along the guide (5, which. is usuallygreater or less than that of the cutter carriage, according to theresult desired.

The mechanism which I have shown for this purpose consists of a gradebar 21 which is swiveled on the model-wheel carriage :2, as by a taperedpin 22 that is journaled in a corresponding socket in the model canriage, and is secured therein by lock nuts The lower end of the gradebar, as shown, swings and slides on a pin -1 on a slide that is mountedin a slideway formed by 'uides 26 and 27 in a base plate Tl e bar has aslot 29. the walls engage the pin 2-1: and thus the is carried by, andturns upon. on the model Carr while it anl slides upon the pin MenusJhait slide 25.

In the same slideway as the slide 25 i: mounted a slide 31 carry ng aplate 32 per-- pendicular to the slide'way, the slide 31 be ing moved bya screw thread 33 on the same shaft as the SCFOW thread 30, the pitch ofthe screw being twice as great as that of the thread 30 for a .ij'easonto be explained later. it shelf or plate 3-1- is l:i:'-:- toned to theplate "8 so as to support model last, as shown in. dotted lines, therebeing a heel plate 35 against which the heel of the last may be rested.A hand wheel 31'; is provided for tu g the screw shalt to draw the pic 1against the toe oi? the model, and to position the pin 24- on which thegrad bar swings, as will be more :li'ull described later. T 1e grade barhas a guideabove and below i s -l'ulpin and a block 38 is mounted insaid guldeway, a clamp 39 being shown as moving the slide 25 in itsslidoway s fill lill) lllO surrounding the grade bar and guideway, andprovided with a thumb screw 40, so that the block 08 may be secured inthe guideway in any desired position. The block 38 carri s pin or screwall upon which one end of alinlr L2 is swiveled, the opposite end 0tsuch link being swlveled on a pin 43 mounted on the cutter headcarriage. The link thus serves to transmit motion from the cutter headcarriage to the modelwheel carriage, the motion transmitted beinggreater or less according as the position of the pin ll mounted on theblock 38 is above or below the level of the pin 22 on which the gradebar is fulcrumed.

Mounted on the grade bar is a bracket is. which carries a plate having aheel rest l-(3 against which the heel of the model can be rested. Theplate 4L5 also has a slideway 4C7 in which is mounted a slide l8carrying a toe plate 49 that can be brought to bear on the toe oi? themodel. As shown in Fig. 2, the slide a8 is provided with a spring 50whose ends bear on the plate 4L5, so as to atl ord l'riction to tend tokeep the slide in any position in which it is left. A. cylinder 51 ismounted on a shaft 52 journaled in bearings on the bracket a l, andplate l5, a hand wheel being provided on said shalt -for the purpose ofturning the cylinder. The cylinder is provided with a chart, which conota series of curved lines 5d that are arranged in ianlike formation, anda line which would be straight it the chart were developed into flatformation instead of shaped around the cylinder. The block 38 or the pinll carries a pointer 56 which is adapted to be set to any of the linesor by shitting the block 38, and the toe plate 418 carries a pointer 57which is arranged directly above the pointer 56 and is adapted to be setthe length of the model away from the heel plate l6, and when suchpointer is thus set, the model line of the chart is intended to beturned until it touches the end of the pointer 57.

in using my grading mechanism and chart in the illustrated embodiment,the toe plate 82 is adjusted to a position the exact length oi the modelaway from the h el plate 35, as by placing the model on the shell g l'with its heel resting against the heel plate '35, and turning the screwshaft. The mechanism is so proportioned that when the toe plate 32 isin. the described position, the pin vertically under the position whichthe center of the model occupies when the model is supported in theswinging frame upon the model heel and toe dogs. As the pitch ot thethread 30 is only on e-hall that of the thread 33, when the toe plate ismoved to accommodate a longer or shorter model, the pin 24 is alwaysmoved just onehalf as much, and thus the pinfl l is always verticallyunder the center of any model mounted on the model toe and heel dogs.when the toe plate 32 is the length of that model away lroln the heelplate 34.

The manner in which the chart calculated is as follows:

ssuming the chart to be formed upon a sheet of flexible material adaptedto be shaped around the cylinder, I desire to form upon the sheet aseries of points in a st night line, such as the series 58 to formed in.a straight line parallel to the axis of the cylinder, said points beingso positioned that when the pointer 56 is set to the proper one of thesaid points, a last can be produced which is exactly the correspondingnumber of sizes longer or shorter than the model last. Such a seriesol'f points will be dill'erently spaced for each different length ofmodel, and I wish to provide series of points for every length of model.and a means for indicatin g which series of points corresponds to agiven length ol model. I have therefore provided the straight diagonalmodel line- 55 to cause the series of points correspomling to a givenmodel length to intersect the said line at a point on said line oppositethe pointer 57 when the latter is a vertical distancc above the heelplate d6 equal to the length oi? the model and registered with sai dpointer when the series otlf points is rotated around a vertical axisinto collinau'ity with the pointers 56 and 57. Of course, the model linecould be placed. at a distance above or below from the position shown,so long as is were parallel to the position shown, and the pointer 57were correspondingly placed. When so arranged and calculated for modelsof all lengths, the points relating to the same size grade :lorrn therespective curved, taulilre lines 54 which I have described, each linebeing the locus of a set of size grade points, and the intersection ofthe curves by a vertica. straight line forming a grading scale TlfOl amodel oi? the corresponding length. When the new last is to be the samelength as the model, the motion transmitted from the cutter carriage tothe model carriage must be unity, which is obtained whim the pin 4:1 ofthe connecting bar 42 is at the level oil the fulcrum pin 22 of thegrade bar, this being true no matter what the length of model used maybe. llheretore, there will be a line which I shall call the model line73, which will be straight and perpendicular to the axis of thecylinder.

In Fig. 10, I. have shown diagrammatically the positions of the ,grradebar, the pivot pin 2stat the lower end of the grade bar, the fulcrum pin22 by which the grade bar is swiveled on the model carriage, and the pin4-1 swiveling the connecting rod 4L2 upon the block 38, which isadjustable in the slideway 37 on the grade bar, these pins and the gradebar being shown in three po sitions, in one of which the model wheel isat the extreme left-hand end of the model,

in another of which the model wheel is at the extreme right-hand end ofthe model, and the third position in which the model wheel is at thecenter of the model. In the latter position the grade bar will always bevertical because, as before explained, the pin 24 is always verticallyunder the center of the model when the latter is mounted on the modellive and dead centers. In the present machine, the distance AB willalways be the same no matter what the length of the model may be. Thedistance C-D will be greater or less, according as the new last is to belonger or shorter than the model to a greater or less extent, the line11-41 being above the line 22-22 when the new last is to be longer thanthe model, and the line ll- 4:1 being below the line 22-22 when the newlast is shorter than the model. The rectilinear distance DF will alwaysbe equal to the length of the new last, and the distance CG always equalto the length of the model. Having, therefore, similar right-angletriangles ABC and AED, the distance CD can easily be calculated for anylength of model, and these distances give the vertical distance of anypoint of the series of points 5872 above or below the model line 73.

Such a chart as I have is in effect a uni versal scale and will enablethe making of a new last which is a given number of inches or sizeslonger than the model last, no matter what the length of the model lastmay be. This has heretofore been impossible of easy and simpleaccomplishment with the typeof grading mechanism I have shown, since theoperative had to experiment with various adjustments of the gradingmechanism until he could get one that would produce the desired additionor subtraction of sizes or half sizes to or from the length of the modellast.

The change in angularity of the connecting rod 42, due to adjustments ofthe block 88, and due to the swinging of the grade bar, would render thecalculation of such a chart as I have described a ditlicult matter, ifit were not for the fact that the described arrangement always sets thelower fulcrum pin 24 vertically below the longitudinal center of thelast, and thus the extreme lefthand and right-hand positions which thegrade bar assumes are symmetrical to the vertical central position, andthe angularity of the connecting rod 42 is therefore the same for thosetwo extreme positions, and being the same can be disregarded.

As my chart is mounted on the grade bar 6 and travels with it, thepointer 56 is never separated from it in any position of the grade bar(as it would be, for instance, if the chart were mounted on the frame ofthe machine in position to be alongside the sition verticahv grade barwhen the grade bar is in its extreme left-hand position). It resultsthat the operative can always see the position of the pointer on thechart at any time, and tell what size of last the lathe is set toproduce. It also eliminates any possibility of error due to the pointer56 not reaching its proper line of movement on the chart, as would bethe case if the scale were stationary and the grade bar were not movedfully into position against it.

The pointer is 'neferably so mounted on the pin etl that it does nothave any turning move-u'ient with the connecting rod, as it would haveif it were mounted on the connecting rod.

I have shown stops H and 75 to position the carriages always in the sameposition at the left hand end of their travel, so that they will alwaysbe in the same position when the grading mechanism is set, and 0 thehnub or stub on the next last shall always be formed of a definitelength and that length the shortest possible consistent with properlyholding the heel. end of such last. I also preferably form theconnecting rod in two parts held together by a clamp ((1 so that thecarriages can alwz be positio'uwl against the steps 74- aud 7:7, asstated.

I claim:

1. In a last lathe, the combinatior ol a model carri a cutter carriage,and grad ing -.necha in for transmitting motion from one of saidcarriages to the other, comprising a lever mounted on a pin carried bythe model, carriage, and on a pin carried on the frame, a connecting rodpivoted to the cutter carriage and adjustably cormected with said lever,and means for adjusting the pin on the frame to a poc itral below themodel, said means compris ng a slide carrying said pin and mounted in aslide iay parallel to the line of movement of said carriages, and auniversal scale for setting the grading mecln anism to grade from modelsofall lengths.

In a lathe, the ('(HllblllzlfiOll of a model carriage, a cutter carriae, and grading inechauisn'i for trair'exnitting motion from one of saidcarriages to the other, comprising lever pivoted on the model car--riage, and on the frame, a connecting); rod pivoted to the cuttercarriage and adjustably connected with said lever. and means foradjusting the pivot on the frame to a position vei't ally central belowthe model. said means comprising a part adapted to be adjusted accordingto the length of the 'model, and connections between said part and saidpivot, such that said pivot is moved parallel to the line of movement ofsaid carriages one-half the distance of movemeui of said part.

3. In a last lathe, the combination of a model carriage, a cuttercarriage, and gradiuu (i ll pit n; a lerer pivoted on the modelcarraise, and on the frame, a connecting rod pivoted to the cuttercarriage and adj 11stablr conne ted with said lever, and n'ieans thepivot on the frame to a in vertically central below the model, saidmeans comprising a slideway parallel to the line oi movement oil? said.carriages, having; twoslides n'ionnted therein, one of which. cm iessaid pivot, means for indi eating; positions oi? the other of saidslides corrcspomlino to the length oi the model, and means fortransinittin, motion from the other oi? said slides to l pivotrarryings-dide, such that said pivotcarryin slide will he noted one-hall" asmach as said second mentioned slide.

+l-. in a last lathe, the combination. of a model carria e, a cuttercarriage, and grad in inech-i sin {or transmitting motion. trom one oi?said carriages to the other, com prising a lever pivoted on the modelcarri e, and on the frame, a connecting rod pivoted to the cuttercarriage and adjust-ably connected with said lever, and means for adjsting the pivot on the frame to a no iion vertically central helorv themodel,

said means comprising; a slideway parallel to the line of movement ofsaid carriages, a

slide mounted in said slideWa-y, and carryino; said pivot, a slidemounted in said slidea for indicating); the length oi the model,

i a scren shailit having; threads adapted to go said slides, the thread.oi? the pivot slide lacing; one-halt the pitch oi? the, other thread.

5. In a last lathe, the combination of a model carr e, a cutter carr' e,and gradii mechanism :ior trans nittin motion to erev one oi. saidcarriages to the other, eompris ng a lever pivoted on. the model carandon the frame, a connecting rod pivoted to the cutter carriage andadjnstably co] acted With said lever, and means for a ,i .ll' the pivoton the :lf'raine to poion min-or central helow the model,

s: l means nprising; a slideiray parallelto the l ne oil? in e nt ofsaid carriages,

- ionnted therein, one Wet, and the other slide 1' ed to he engaged byan aid slideway having an to he engaged by the model, and the screwshaft a lay screw threads, the v t carrying; slide being; one halt thepitch oi? oth thread.

la a lathe, the combination of a model. carriaglge, acntter carriage,grading], mechanism adapted to transntiit graded moticn from oit saidcarriages to the other and comprising; a part adjustable to grade saidmotion, and a series of scales graduated.

mounted open. as to always he in Ol lo'li'tl'tli'o relation to said 7.in a last lathe, the combination of a model cai'riage, a cuttercarriage, grading mechanism adapted to transmit graded motion from oneof said carriages to the other, and romnrising a connecting rod and auniversal scale, and means for causing the can treine positions 01"- theconnecting rod to have a common degree of angnlarity determined by thelength of travel of the model carriag'e.

8. In a last lathe, the combination of a model carriage, a cuttercarriage, grading mechanism. adapted to transmit 'aded motion from oneof said. carriages to the other, and con'iprisingr a connecting rod, auniversal scale by which said mechanism is adapted to he to grade fromany model, and. means for cansinp; the extreme positions of theconnecting; rod to balance each other, irres 'iective oi. the length ofthe model.

9. in a last lathe, the combination of a model carriage, a cuttercarriage. minding mechanism adapted to transmit graded motion from oneoil? said carriages to the other, and co1nni'..'..iin,o; a connectingrod, a universal scale by which said grading; mechani m is adapted to beset to grade from any odel, and means adapted to render the positionsoi? the connecting red, when the model carriage is at the extremities ofthe model, symmetrical irrespective of the model length.

1.0. In a last lathe, the combination of a model cari' re, a cuttercarriage, grading mechanism adapted to transmit graded motion :tr ..none of said carriages to the other, and comprising}; a connecting rod, auniversal scale by which said grading mechanism. is adapted to be set tograde from any model, and means adapted to render the i iositions oi theconnecting rod, when the model carr' ,e is at the entrcniit" oi" themodel, 01 the same degree of angnlarity dependent noon the length oftravel of the model carriz 11. In a la.

it lathe, the combination of a model car] a cutter carriage, gradingmechanism aoented to transmit graded motion :lroin one of said carriagesto the other, and comprising a connecting rod, a uni versal scale bywhich said grading mechanism is adapted to he set to grade from a modelof any length, and means adapted to render the positions oi theconnecting); rod, when the model carriage is at the extremities ot themodel, such that the singularities oi said connecting rod shall canceleach other irrespective of the model length.

In a last lathe, the combination of a elation to said part,

model carriage, a cutter carriage, grading mechanism adapted to transmitgraded motion from one of said carriages to the other, and comprising aconnecting rod, a universal scale by which said grading mecha nism isadapted to be set, and means adaptcd to render the positions of theconnecting rod to grade from any model, When the model carriage is atthe extremities of the model, such that the angularities of saidconnecting rod shall cancel each other, said means comprising deviceswhereby the axis of the crank forsaid connecting rod may be fulcrumed,so as, in effect, to be central of the length of the model.

13. In a last lathe, the combination of a model carriage, a cuttercarriage, grading mechanism adapted to transmit graded motion from oneof said carriages to the other, and comprising a part adjustable tograde said motion, and a series of scales graduated to produce thegrades corresponding to different model lengths having a fixed relationto the path of movement of said part, so as-to always be in operativerelation to said part.

14:. In a last lathe, the combination of a model carriage, a cuttercarriage, grading i'nechanism adapted to transmit graded motion from oneof said carriages to the other, and comprising a part adjustable tograde said motion, and a series of scales adapted to be used in settingsaid part, said series of scales being mounted upon a cylinder, saidcylinder being mounted upon said grad ing mechanism so as to always bein operative relation to said part.

15. In a last lathe, the combination of a model carriage, a.cutter-carriage, grading mechanism adapted to transmit graded inotionfrom one of said carria s to the other, and comprising a part ad ble tograde said motion,and a series of scales adapted to be used in settingsaid part, said series of scales being mounted upon a cylinder, saidcylinder being mounted upon said grading mechanism so as to always be inoperative relation to said part, said series of scales comprising aseries of lines Whose intersee tions With the path 01'? movement of saidpart in a given position of said scales, indicate positions of said partto obtain predetermined variations in length of a given model.

16. In a last lathe, the combination of a model carriage, a cuttercarriage, grading mechanism adapted to transmit graded n1otion from oneof said carriages to the other, and comprising a part adjustable tograde said motion, a series of scales adapted to be used in setting saidpart, said series oi? scales being mounted upon a cylinder, saidcylinder being mounted upon said grading; mechanism so as to always bein operative said series o2 581i";

c()ill )ll5lil,',f a series oi lines \vhosc inlcrsections with the pathof movement of said part in a given position of said scales, indicatepositions of said part to obtain prc determined variations in length ofa given model, and means for indicating the relative positions of said,lines and part for given length. of model.

17. In a last lathe, the combination ol :1 model carriage, a cuttercarriage, grading mechanism adapted to transmit graded motion from Oneof said carriages to the other, and comprising a part adjustable tograde said motion, a series of scales adapted to be used in setting saidpart, said series oi scales being mounted upon a cylinder, said cylinderbeing mounted upon said grading mechanism so as to always be inoperative relation to said part, said series of scales comprising aseries of lines Whose intersections with the path of moven'ient of saidpart in a given position of said scales, indicate positions of said partto obtain predetermined variations in length of a given model, and meansfor indicating the relative positions of said lines and part for a givenlength of model, said means comprising a line at an angle to said seriesof lines.

18. In a last lathe, the combination oi a model carriage, a cuttercarriage, grading mechanism adapted to transmit graded motion from oneof said carriages to the other and comprising a part adjustable to gradesaid motion, a series of scales adapted to be used in setting said part,said series of scales being mounted upon a cylinder, said cylinder beingmounted upon said grading mechanism so as to always be in operativerelation to said part, said series of scales comprising a series oflines Whose intersections with the path of movement of said part in agiven position of said scales, indicate positions of said part to obtainpredctermined variations in length of a given model, means forindicating the relative positions of said lines and part for a givenlength of model, said means comprising a line at an angle to said seriesof lines, and a pointer for indicating the proper position of saidangled line for a given model.

19. In a last lathe, the combination of a model carriage, a cuttercarrii ge, grading mechanism adapted to transmit graded motion from oneof said carriages to the other, and comprising a part adjustable tograde said motion, a series oi scales adapted to be used in setting saidpart, said. series oi scales being mounted upon a cylindcr, saidcylinder being mounted upon said grading mechanism so as to always be inoperative relation to said part, said series of scales comprising aseries of lines Whose interseciJlOZIS WitlI the path of movement of saidpart in a given position of said scales, indicate positions of said partto obtain predeliH) ill)

til

iii

termined variations in length oi a given model, means for indicating therelative positions 01? said lines and part for a given length of model,said means comprising a line at an angle to said series oi llnes, apointer for indicationthe proper position [lll said diagonal line tor agiven model, and means for positioning said pointer according): to thelength of the model.

910. lo a last lathe, the combination 01 a model carriage, a cuttercarriage, grading mechanism adapted to transmit graded motionil'rom oneof said carriages to the other, and comprising; a part adjustable tograde said motion, a series of scales adapted to he used in setting saidpart, said series ct scales heir i mounted upon a cylinder, saidcylinder being); mounted upon said grading mechanism so as to always bein operative relation to said part, said series oil scales comprising};a series oi. lines whose intersections with the path o'l movement ofsaid part in a given position of said scales, in

d ate positions of said part to obtain prcdeternz red variations inlength oil? a given model, means for indicatingthe relative positions ofsaid lines and part for a given length m model, said means comprising aline at an an le to said series of lines, a ntcr 'lor ii'ldusatiing theproper position of rid angled line tor a ven model, and means :lorpositioning); said pointer according to the length oi the model, saidn'lex'ins for no. l ioni c; said pointer comprising an abutment for oneextremity oi: the model, and a slide carrying said pointer and morabletmvard and :t'i'on'i said abutment.

all. In a last lathe, the combination 0i. a model carriage, a cuttercarriage, grading mechanism ad. ted to transmit or ided mo tion troinone oi said carriages to the other. coi'npri "1:: a lever itulcruined onthe frame,

and adapted to he swu o; by aid model car- 5, a connecting rod pivoted.to said cutter ,2, and adjnstahly connected with said cans for adjustingthe fulcrum oil d lever to a position ver' sally central r. the model, aseries of scales carried li v said lever for adjustine; said connectingrod on said lever, said serr of scales being); mounted on a cy inderparallel with said lever, and conugnasin a line perpendicular to axisoil: said cylinder to]: positioning said connecting rod in neutralposition, and a tau-shaped series oil: lines approaching; parallelism tosaid line at one extremity thereof.

ln a last lathe, the combination oi? a model carriage, a cuttercarriage, radlng inechanisin adapted to transmit graded mowith saidlever, means ifor adjusting the fulcrum of said lever to a positionverti cally central. below the model, a series 01 scales carried by saidlever for adjusting said connecting rod on said lever, said series ofscales being mounted on a cylinder paral. lcl with said lever, andcomprising a line perpendicular to the axis of said cylinder forpositioning said connecting rod in neutral position, a flzlirsliapeclseries of lines approaching parallelism to rid lineal; one extremitythereof, and a model line for indicating the position of said cylinderfor a particular model.

23. In a last lathe, the combination oil a model carriage, a cuttercarriage, grading mechanism adapted to transmit graded niol'ion from oneof said carriages t0 the other, comprising a lever fulcruined on theframe, and adapted to be swung, by said model carriage, a connecting rodpivoted to said cutter carriage, and adjustahly connected with saidlever, means for adjusting the fulcrum of said lever to a positionvertirally central below the model, a series oil'i scales carried bysaid lever for adjusting said connecting rod on said lever, said seriesoil? scales being mounted on a cylinder parallel with said lever, andcomprising a line perpendicular to the axis oi? said cylinder forpositioning said connecting rod in nontral position, atan-shaped seriesof lines approaching parallelism to said line at one extremity thereof,a model line for indicating; the position oi. said cylinder for aparticular model, and a pointer adapted to be positioned according tothe length of the model, for indicating the proper position of saidmodel line.

Ell. A scale for a last turning lathe comprising a base linecorresponding; to the model size, and curves corresponding to dillcrentstyles or]? other sizes of lasts, saidcarves each consisting cl: aseries of points at distances from, said base line proportional to thedifference in size plus an extension. determined by the style oil lastand also pro mrtional to a leverage oi the grading mechanism which.leverage varies with the length of the model.

A. scale For a last turning lathe cone raising a base l inccorresponding to the iruidelv size, cnrv r-l corresponding to differentdos oi other sizes of lasts, said curves each consisting; or a seriesotpoints at distances from. said base line proportional to thedifference in size plus an extension determined by the stvle of last andalso proportional to a leverage oi the 1 i"adi11g mechanism, whichleverage vari length of the model, said scale also having a referenceline comprising; points respectively having a definite relation to saidfirst nn-zntiened points and spaced from said base line distancesproportional respectively to with the I the lengths of the correspondingstyles of lasts of the same size.

26. The method of determining the position of points upon a gradingscale corresponding to difierent sizes of a given model of last, whichcomprises establishing on said scale a base line corresponding to themodel. size, and locating a scale point for another size at a distancefrom said base line, proportional to the difference in size plus anextension determined by the style of the last.

27. The methodof determining the position of points upon a grading scalecorresponding to dilferent sizes a given model of last, which comprisesestablishing on said scale a base line corresponding to the model size,and locating a curve corresponc ing to different styles of another sizeor last, by progressively plotting a series of points at a distance fromsaid base line proportional to the difierence in size plus extensionsrespectively determined by the styles o1"- last corresponding to thepoints.

28. The method of determinin the position of points upon a grading scalecorresponding to different sizes or" a given model of last, whichcomprises establishing on said scale a base line corresponding to themodel size, locating a scale point for another size at a distance fromsaid base line, proportional to the difl'erence in size plus anextension determined by the style of the last, and plotting on the scalea reference point having a definite relation to said first mentionedpoint and spaced from said base line a distance proper ional to thelength of the extension for the corresponding style of last.

29. The method of determining the position of points upon a gradingscale corresponding to different sizes of a given model of last, whichcomprises establishing on said scale a base line corresponding to themodel size, locating a curve corresponding to different styles ofanother size of last, by progressively plotting a series of points at adistance from said base line proportional to the difference in size pluseXt-ensions respectively determined by the styles of last correspondingto the points, and plotting on the scale a'reference line comprisingpoints re spectively having a definite relation to said first mentionedpoints and spaced from said base line distances proportionalrespectively to the lengths of the corresponding styles of last.

30. The method of determining the po sition of points upon a gradingscale corresponding to diflerent sizes of a given model of last, whichcomprises establishing on said scale a base line corresponding to themodel size, locating a cur e corresponding to different styles ofanother size of last, by pro gressively plotting a series of points at adistance from said base line proportional to the difference in size plusextensions rcspcctively determined by the styles 01" last correspondingto the points, and plotting on the scale a rei'ierenco line comprisingpoints respcctively having a definite relation to said first mentionedpoints and spaced from said base line distances proportional.respectively to the lengths of the corresponding styles oi lasts of thesame size.

In a machine of the class described, a carriage on the model side, acarriage on the work side, and grading mechanism for ctfecting arelative movement between them comprising a part adjustable to gradesaid movement and a universal chart for setting said part, mounted onthe grading mechanism in such manner as always to be in operativerelation to said part.

32. In a machine or the class described, a carriage on the model side, acarriage on the vorlr side, and grading mechanism for cl"- iecting arelative movement between them comprising a part adjustable to gradesaid movement and a universal chart for setting said part, mounted onthe grading mechanism in such manner as always to be in operativerelation to said cart, said chart showing the locus of the settingpoints for said part for a certain grade from models of all lengths.

In a machine of the class described, a carriage on the model side, acarriage on the work side, and grading mechanism for el fecting arelative movement between them comprising a part adjustable to gradesaid novement and a universal chart for setting said part, mounted onthe grading mechanism in such manner as always to be in operativerelation to said chart, said chart containing the loci of the settingpoints of said part, relating respectively to the differei'lt gradesfrom models of all lengths.

34. In a machine of the class described, a carriage on the model side, acarriage on the work side, and grading mechanism for offecting arelative movement between them comprising a part adjustable to gradesaid movement and a. universal chart for setting said part, mounted onthe grading mechanism in such manner as always to be in operativerelation to said part, said chart containing a curve whose ordinatesmeasured from a line of reference correspond to a continuous series ofsettings of said part corresponding to a certain grade from a series ofmodels of continuously varying length.

85. In a machine or the class described, a carriage on the model side, acarriage on the work side, and grading mechanism for effecting arelative movement between them comprising a part adjustable to gradesaid movement and a universal chart for setting said part mounted on thegrading mechanism in such manner as always to be in opertil) ill)

lll]

ative relation to said part, said chart showpointer to bring the properpoint of the ing the locus for the setting points for said curve intothe path of adjustment of the part for a certain grade from models ofall said part. a 10 lengths, a pointer constructed and arranged Intestimony that I claim the foregoing I 5 to he moved to measure thelength of the have hereunto set my hand.

model and a point on every ordinate of the said curve arranged forcooperation with the EDWIN J. PRINDLE.

